1. Field of the Invention
The present invention relates to an ultrasonic imaging apparatus that transmits ultrasonic waves to a subject and receives the reflected waves to measure the state of a site of the subject, and also relates to a stress echo browsing apparatus.
The present invention particularly relates to a technology that allows an ultrasonic imaging apparatus configured to change the magnitude of a load (stress, referred to as “load” hereinafter) in a plurality of examination stages to apply to a site of a subject in a plurality of types of stress echocardiographies and configured to measure the state of the site by ultrasonic waves every time applying the load, to acquire a plurality of types of parameters signifying the state of the site in each of the examination stages, store the plurality of types of parameters in categories and easily recognize the change of the parameters in the above measurement.
2. Description of the Related Art
For example, in a stress echocardiography, regarding deterioration of the cardiac function that does not appear in a normal resting state, an ischemic state is generated by applying a load to a heart through an exercise or with a medical agent. Since changes are thereby caused in cardiac ventricles or atriums, particularly in systolic functions or diastolic functions of the left ventricle, it is possible to diagnose constructed sites of blood vessels or regions with deteriorated heart functions (refer to Japanese Unexamined Patent Application Publication JP-A 2006-26151). Furthermore, in order to diagnose the degree of seriousness, the state of the load on the heart is set in stages, which are referred to examination stages, phases, or stages (hereinafter referred to as “phases”).
In a diagnosis, the wall motion of a heart is observed or numerically analyzed in real time or with moving images, and the amount of change thereof is evaluated qualitatively and quantitatively.
The numerically analyzed evaluation is conventionally performed on the entire heart or a local part thereof by a method of directly analyzing the motion of a heart, measuring the ventricular volume or the rate of change, or analyzing the blood flow velocity.
In an ultrasonic imaging apparatus (e.g., JP-A 2006-26151), a load is applied to a site while the magnitude thereof is changed in each of a plurality of phases to perform a stress echocardiography. As described in JP-A 2006-26151, the load is, for example, an exercise load and a dobutamine stress. As a typical example of the stress echocardiography based on the exercise load, measurements are executed on a site in three phases, i.e., “before loading,” “during loading (at peak load)” and “after loading (recovery).” Furthermore, as a typical example of the stress echocardiography based on the dobutamine stress, measurements are executed on a site in six phases, i.e., “before loading,” “10γ loading,” “20γ loading,” “30γ loading,” “40γ loading (at peak load)” and “after loading (recovery).” The number of the phases is not limited by these examples, but the minimum number of the phases in the stress echocardiography is two phases, i.e., before loading and during loading (e.g., peak load).
Then, the ultrasonic imaging apparatus analyzes the motion or strain at a local site in a site image acquired with ultrasonic waves at the time of measurement of each phase, and calculates the values of a plurality of types of parameters signifying the state of the site. In other words, the values of a plurality of types of parameters relating to the motion or strain at the local site are calculated for each phase. Then, such a comparison of obtaining the difference of parameter values of adjacent phases is performed, and data indicating the motion state of the local site is acquired.
In the abovementioned conventional art, when a single type of stress echocardiography is executed, the parameter in each phase is obtained to calculate the amount of change. Then, a list of examination results of the type of stress echocardiography is displayed or outputted.
However, after the stress echocardiography is finished or when it is desired to interpret images to create a report on another day, it is difficult to, e.g., quantitatively grasp the amount of change in Phases 4 through 6 with reference to Phase 2 from the examination results of the stress echocardiography of Phases 1 through 6 under Dobutamine stress A. In other words, the apparatus is not configured to individually output the parameters from the examination results, and therefore, it is impossible to, e.g., derive the parameter of Phase 2 under Dobutamine stress A.
As a result, in the abovementioned conventional art, it is difficult to recognize or visually recognize the amount of change in a desired format with regard to a specific type of parameter.